Invalidate caches
When you invalidate the cache, JetBrains Rider removes the cache files for all solutions ever run in the current version of the IDE. The files will be recreated the next time you open these projects.
Clear system cache
Select from the main menu.
In the Invalidate Caches dialog, you can select additional actions that the IDE will perform while removing the cache files:
Clear file system cache and Local History: remove the virtual file system cache together with the information stored in Local History.
This action might be helpful for troubleshooting purposes when the usual cache invalidation is not enough to solve the problem.
Clear VCS Log caches and indexes: remove the cache and indexes of the VCS Log.
Enable this option if you are certain that your VCS Log indexes are broken, for example, if the Log search doesn't work correctly.
ReSharper Caches: this option is always selected. It's there to remind you that the caches of .NET code analysis engine will be also removed when you clear the IDE caches.
Delete embedded browser engine cache and cookies: remove the cache files and cookies that are stored in the built-in JCEF browser.
These files rarely get broken. This option allows you to invalidate the cache while keeping JCEF cookies and caches intact.
Click Invalidate and Restart.
If you click Just restart, cache files won't be deleted, and the selected optional actions won't be applied.
For more information about storage of various user-specific files, refer to Directories used by the IDE.